Permeability change

The probe receives a signal when either the driver or detector coil passes a flaw or other feature in the tube A signal is produced over the full length of the flaw. It is affected by geometry and permeability changes which cause the instrument zero to wander. 

Signals from geometry, residual magnetism or slow permeability changes are reduced or eliminated. 

Leive L (1968) Studies on the permeability change produced in coliform bacteria by ethylenediaminetetraacetate. J Biol Chem 243 2373-2380. 

Granger, D.N., McCord, J.M., Parks, D.A. and FloUwarth, M.E. (1986). Xanthine oxidase inhibitors attenuate ischaemia-induced vascular permeability changes in the cat intestine. Gastroenterology 90, 80-84. 

Bhalla, D.K., Mannix, R.C., Lavan, S.M., Phalen, R.F., Kleinman, F.T. and Crocker, T.T. (1987). Tracheal and bron-choalveolar permeability changes in rats inhaling oxidant atmospheres during rest or exercise. J. Toxicol. Environ. Health 22, 417-437. 

The reported (14) mechanisms of action of allelochemlcals Include effects on root ultrastructure and subsequent Inhibition of Ion absorption and water uptake, effects on hormone-induced growth, alteration of membrane permeability, changes In lipid and organic acid metabolism, inhibition of protein synthesis and alteration of enzyme activity, and effects on stomatal opening and on photosynthesis. Reduced leaf water potential Is one result of treatment with ferulic and p-coumaric acids (15). Colton and Einhellig (16) found that aqueous extracts of velvetleaf (Abutllon theophrastl Medic.) Increased diffusive resistance In soybean fGlycine max. (L.) Merr.] leaves, probably as a result of stomatal closure. In addition, there was evidence of water stress and reduced quantities of chlorophyll In Inhibited plants. 

Weiss et al. [11] reported permeability changes for a neutral solute across a poly(MAAc) membrane. These changes were attributed to the increase in pH... 

Mazumder S. and Wolf K.H. Differntial swelling and permeability change of coal in response to C02 injection for ECBM. 2008 International Journal of Coal Geology 74(2) 123-138. 

Vigneault, B., Percot, A., Lafleur, M. and Campbell, P. G. C. (2000). Permeability changes in model and phytoplankton membranes in the presence of aquatic humic substances, Environ. Sci. Technol., 34, 3907-3913. 

Neurological effects occurred in animals exposed to endrin. Behavioral effects (Gray et al. 1981), hyperexcitability, tremors, and convulsions (Deichmann et al. 1970 NCI 1978 Treon et al. 1955) were reported. Irregular EEG recordings were observed in rats (Speck and Maaske 1958). There is some evidence to show that occurrence of convulsions is related to blood-brain barrier permeability changes (Speck and Maaske 1958). 

In addition to studies with whole cells and tissues, it has also been shown that the permeability of isolated organelles can be altered by ozone exposure. For example, Lee (11) showed that ozone altered the permeability of tobacco mitochondria, and Coulson and Heath (12) reported membrane permeability changes of isolated chloroplasts after ozone exposure. 

When ozone is turned-off at some point during this rapid loss period, the high rate of Rb leakage ceases within 2-3 min and returns to the control leakage rate. Thus, this permeability change, measured by efflux, appears to be reversible, as is net K+ leakage measured with the cation electrode. ... 

In conclusion, it is our view that K+ plays a dominant role in maintaining a favorable plant cell water status and that the deleterious effects of ozone occur primarily due to disruption of this normal ionic balance. We currently visualize the following scheme of ozone damage (a) ozone attack of an SH group or fatty acid residue (b) permeability changes of the membrane leading to loss of both K" " and osmotic water (c) inhibition or loss of K" " pump activity for reacquisition of lost K+ (d) loss of a critical level of ion and (e) gross disruption of cellular metabolism. 

Figure 15. Possible mechanism of guest-induced permeability changes for electroactive markers by oriented membranes of the calix[61arene hexaester 28 (R = Bu ) in the cases that (a) anionic, (b) cationic, and (c) neutral markers are used.

Table 4. Selectivities of Guest-Induced Permeability Change for Oriented Monolayer of Calix[6]arene Hexaester 28 (R = BuV ...

Notes juest-induced permeability changes at 20 C and pH 6.0 (0.1 M Tris-HCl buffer) were estimated on the basis of cyclic voltammogram area. 

Schematic diagram of the ion permeability changes and transport processes that occur during an action potential and the diastolic period following it. Yellow indicates inward (depolarizing) membrane currents blue indicates outward (repolarizing) membrane currents. Multiple subtypes of potassium and calcium currents, with different sensitivities to blocking drugs, have been identified. The right side of the figure lists the genes and proteins responsible for each type of channel or transporter.

When an excitatory pathway is stimulated, a small depolarization or excitatory postsynaptic potential (EPSP) is recorded. This potential is due to the excitatory transmitter acting on an ionotropic receptor, causing an increase in cation permeability. Changing the stimulus intensity to the pathway, and therefore the number of presynaptic fibers activated, results in a graded change in the size of the depolarization. When a sufficient number of excitatory fibers are activated, the excitatory postsynaptic potential depolarizes the postsynaptic cell to threshold, and an all-or-none action potential is generated. 

In the majority of patients with sickle cell disease, anemia is not the major problem the anemia is generally well compensated even though such individuals have a chronically low hematocrit (20-30%), a low serum hemoglobin level (7-10 g/dL), and an elevated reticulocyte count. Instead, the primary problem is that deoxygenated HbS chains form polymeric structures that dramatically change erythrocyte shape, reduce deformability, and elicit membrane permeability changes that further promote hemoglobin polymerization. Abnormal erythrocytes... 

The Rb-82 generator permits serial studies in the same patient as often as every 10 minutes with 20-60 mCi of Rb-82 for rapid bolus intravenous infusion. Inherent in the administration of high levels of Rb-82 activity is the need for precise flow control from an automated system to deliver the desired amount of radioactivity. The development of the alumina column parameters and the elution protocol as well as the automated microprocessor system controller are presented here. Some of the details of this system have been discussed in earlier publications (15,21). Generator produced Rb-82 is used as a diffusible flow tracer in myocardial perfusion studies and as a nondiffusible tracer in brain studies to assess blood brain barrier permeability changes in patients with brain tumors or Alzheimer s type dementia. 

The major secondary events are changes in membrane structure and permeability, changes in the cytoskeleton, mitochondrial damage, depletion of ATP and other cofactors, changes in Ca2+ concentration, DNA damage and poly ADP-ribosylation, lysosomal destabilization, stimulation of apoptosis, and damage to the endoplasmic reticulum. 

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